Strasbourg Oncologie Liberale, Strasbourg, France.
Geneva University Hospitals, Geneva, Switzerland.
Technol Cancer Res Treat. 2020 Jan-Dec;19:1533033820947759. doi: 10.1177/1533033820947759.
A 2-level factorial pilot study was conducted in 2007 just before starting a randomized clinical trial comparing tomotherapy and conventional radiotherapy (CR) to reduce cardiac and pulmonary adverse effects in breast cancer, considering tumor laterality (left/right), target volume (with/without nodal irradiation), surgery (tumorectomy/mastectomy), and patient position (prone/supine). The study was revisited using a penalty score based on the recently developed mean absolute dose deviation (MADD).
Eight patients with a unique combination of laterality, nodal coverage, and surgery underwent dual tomotherapy and CR treatment planning in both prone and supine positions, providing 32 distinct combinations. The penalty score was applied using the weighted sum of the MADDs. The Lenth method for unreplicated 2-level factorial design was used in the analysis.
The Lenth analysis identified nodal irradiation as the active main effect penalizing the dosimetry by 1.14 Gy (P = 0.001). Other significant effects were left laterality (0.94 Gy), mastectomy (0.61 Gy), and interactions between left mastectomy (0.89 Gy) and prone mastectomy (0.71 Gy), with P-values between 0.005 and 0.05. Tomotherapy provided a small reduction in penalty (reduction of 0.54 Gy) through interaction with nodal irradiation (P = 0.080). Some effects approached significance with P-values > 0.05 and ≤ 0.10 for interactions of prone × mastectomy × left (0.60 Gy), nodal irradiation × mastectomy (0.59 Gy), and prone × left (0.55 Gy) and the main effect prone (0.52 Gy).
The historical dosimetric analysis previously revealed the feasibility of tomotherapy, but a conclusion could not be made. The MADD-based score is promising, and a new analysis highlights the impact of factors and hierarchy of priorities that need to be addressed if major gains are to be attained.
2007 年，在开始一项比较托姆治疗和常规放射治疗（CR）以减少乳腺癌心脏和肺部不良反应的随机临床试验之前，进行了一项 2 水平析因性先导研究，考虑了肿瘤侧（左/右）、靶区（有/无淋巴结照射）、手术（肿瘤切除术/乳房切除术）和患者体位（俯卧/仰卧）。该研究使用基于最近开发的平均绝对剂量偏差（MADD）的惩罚评分进行了重新评估。
8 名患者具有独特的侧位、淋巴结覆盖和手术组合，分别在俯卧位和仰卧位进行了双托姆治疗和 CR 治疗计划，提供了 32 种不同的组合。惩罚评分是通过 MADD 的加权和应用的。采用 Lenth 法对未复制的 2 水平析因设计进行分析。
Lenth 分析确定淋巴结照射是影响剂量学的主动主要效应，使剂量学降低 1.14Gy（P=0.001）。其他显著效应包括左侧（0.94Gy）、乳房切除术（0.61Gy）和左侧乳房切除术与俯卧位乳房切除术之间的相互作用（0.71Gy），P 值在 0.005 至 0.05 之间。托姆治疗通过与淋巴结照射的相互作用（P=0.080），提供了较小的惩罚减少（减少 0.54Gy）。一些效应接近显著，P 值为 0.05 至 0.10 之间，包括俯卧位×乳房切除术×左侧（0.60Gy）、淋巴结照射×乳房切除术（0.59Gy）和俯卧位×左侧（0.55Gy）以及主要效应俯卧位（0.52Gy）。
先前的剂量学分析表明托姆治疗是可行的，但无法得出结论。基于 MADD 的评分很有希望，如果要获得重大收益，需要突出重点并解决各种因素和优先级的影响。
